Identification of Novel Glycans with Disialylated Structures in α3 Integrin from Mouse Kidney Cells with the Phenotype of Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) is a common genetic disorder caused by mutations in the Pkd1 or Pkd2 genes, in which large cysts replace normal kidney tissue, leading to end-stage kidney disease. In this study we have utilized a powerful nano-HPLC–mass spectrometric approach to characterize patterns of normal and abnormal N-linked glycosylation of α3 integrin subunit in Pkd1–/– cells derived from mouse kidneys. Higher molecular weight glycan structures with a different monosaccharide composition were observed at two sites, namely, Asn-925 and Asn-928 sites in α3 integrin isolated from Pkd1+/+ cells compared with Pkd1–/– cells. In addition, an unusual and unique disialic acid glycan structure was observed solely in Pkd1–/– cells. Thus, these studies suggest that abnormal protein glycosylation may have a role on the pathogenesis of cyst formation in ADPKD.